Doors having wood composite molded door facings are well known in the art. Typically, a perimeter frame is provided, which includes first and second vertically extending stiles and at least first and second horizontally extending rails attached together, frequently by an adhesive such as polyvinyl acetate, to form a rectangular frame. A lock block may also be utilized to provide further support for a door handle and/or a locking mechanism at the periphery of the door. The lock block is preferably secured to a stile and/or a rail. Door facings are adhesively secured to opposite sides of the frame, and the door facings (also known as door skins) typically are identical in appearance.
The resulting door includes a void or hollow space defined by the opposing door facings and perimeter frame. This void typically causes the door to be lighter than a comparably sized solid, natural wood door, which is not as desirable for many consumers. In addition, the sound and/or heat insulation provided by such doors may not be satisfactory. Therefore, it is often desirable to use a core material (e.g., core pieces or components) to fill the hollow space.
A suitable core material should provide the door with a desirable weight, for example the weight of a similarly-styled natural solid wood door. In addition, a core material should provide the door with a relatively even weight distribution. The core material should also be configured to match the dimensions of the interior space defined by the facings and frame with sufficiently close tolerances so that optimal structural integrity and insulation properties are achieved. The core material may also provide noise attenuation, thermal resistance and other properties that enhance the functionality of the door. Another function of the door core is to provide resistance to distortion. This distortion includes both distortion that might be built in to the door during assembly, and also distortion that might result later from exposure to moisture, for example.
Door facings may be molded from a planar cellulosic fiber mat to include one or more interior depressions or contours, such as one or more square or rectangular depressions which extend into the hollow space of a door assembly relative to the plane of an outermost exteriorly disposed surface of the door. For example, a door facing may include molded walls having a plurality of contours that include varied curved and planar surfaces that simulate a paneled door. One type of door facing commonly referred to as shaker or shaker-styled is characterized at least one rectangular depression in the door facing.
If the door facings are contoured to include one or more depressions, the interior void of the door assembly will have varying dimensions given the facings are secured to co-planar stiles and rails. When providing a core material or component within the void of a door assembly having such contoured facings, it is necessary to compensate for the varying dimensions of the void.
In the past, various materials, such as wheat board, corrugated cardboards, and/or paper, have been used as the core material. However, due to the contoured door facings, the thickness of the core material varies within a door, which may result in lowered strength and stability in the thinner areas (formed by depression in the door facing). As a result, the door may be susceptible to distortion, such as when it is exposed to high humidity. This is particularly true for a shaker door, due to the relatively large panel area.
Therefore, there remains a need for a shaker door that contains improved dimensional stability and reduced distortion when exposed to high humidity.